Third generation (3G) mobile networks include at least one entity known as a home location register, or HLR. One of the duties of an HLR is to keep track of the location of mobile subscribers. Information about a subscriber's current location is typically maintained in a database on the HLR. Each HLR typically maintains information for a large number of subscribers, e.g., hundreds of thousands to millions of subscribers. For example, if each HLR can store information for ten million subscribers, a network operator having eighty million subscribers would therefore need about eight HLRs. HLRs provide subscriber location information in response to receiving a subscriber location query from another node in the network, such as a mobile switching center (MSC). For example, when an MSC receives a request to set up a call between the calling party and a mobile subscriber, the MSC must first determine the current location of the mobile subscriber in order to route the call setup request to the network equipment currently serving that subscriber, which the MSC does by sending a query to the HLR. If the network has multiple HLRs, the MSC needs to send the query to the correct HLR, i.e., to the HLR that maintains information for the particular mobile subscriber that the calling party is trying to reach.
Telecommunications networks that use system signaling 7 (SS7) for network signaling typically have one or more signaling transfer points, or STPs, for routing signaling messages related to call setup, registration of a device to the network, location updates, and so on. As a nexus of signaling traffic, STPs are well-placed to make routing decisions based on, for example, subscriber identities. Thus, the MSC may be provisioned to send all location queries to the nearest STP and let the STP figure out which HLR should receive that particular query.
In conventional telecommunications networks, an STP may access multiple HLRs, but HLRs are typically not shared among STPs. As a result, subscriber location information is distributed across the network in one of the potentially many HLRs in the system. When the location of a subscriber needs to be determined, the STP must first identify which of the many HLRs maintains that subscriber's information before routing the location query to that HLR. If the subscriber's information is not contained in any of the HLRs that the STP is associated with, the STP may need to forward the location query to another STP, which may forward the query to yet another STP, and so on, until it gets to the STP that is associated with the HLR that contains the subscriber's current location. Only then can the proper HLR be queried, and the query result must be sent back through the network until it is received by the MSC that sent the original query. This multi-step process is cumbersome and inefficient.
Accordingly, there exists a need for a centralized repository that stores current location information for all mobile subscribers in a telecommunications network. Furthermore, such a centralized repository should be able to be dynamically updated using information from a multitude of sources, such as the nodes which report changes in a mobile subscriber's location and/or signaling routing nodes that route this information throughout the network. In short, there exists a need for methods, systems, and computer readable media for providing a triggerless centralized location server.